In this chapter, Jehoshaphat becomes king over Judah.
In some ways, the life of Jehoshaphat is similar to the life of Asa. This chapter in particular seems to mimic the early days of Asa's reign when it says that Asa followed the Lord (2 Chron 14:2-5), was rewarded with peace (2 Chron 14:5-7), he uses peace to build out fortified cities (2 Chron 14:6-7) and concludes with a brief description of his military forces from Judah and Benjamin (2 Chron 14:8). This chapter follows a similar pattern with Jehoshaphat's religious dedication in verses 3-9, God rewarding him with peace in verse 10-11, the construction of fortified cities in verses 12-13, and the census of military forces in verses 14-18.
In fact, I would go further than just saying they have similar lives; I think there is a similarity in the literary pattern between 2 Chronicles 14 and this chapter in the way that the two chapters first describe the king's moral character, then describe God's response, and conclude with a kind of survey of the king's military organization of the kingdom. The parallels will drop off slightly in the next chapter, but in both cases it seems that the census of Judah's army precedes a military engagement (in the case of Asa, when he was invaded by the Cushites, and in the case of Jehoshaphat, when he allies with Ahab to attack Aram which is described in the next chapter).
This chapter does not have any equivalent passage in Kings. When you read 1 Kings 15, the death of Asa ends its description of the history of Judah and it immediately launches into a long segment about the kings and history of Israel with a particular emphasis on the conflict between Ahab and Elijah. This story is entirely omitted from Chronicles. Instead, 1 Kings 22:41-50 describes the life of Jehoshaphat and it leaves out most of the details about Jehoshaphat's religious reforms.
Overall, this chapter doesn't have much in the way of new action or things happening. I see it as more of an overview of Jehoshaphat's character and the tenor of his reign. The real story begins in the next chapter when Jehoshaphat allies with Ahab to attack Aram.